Book/Dissertation / PhD Thesis

FZJ-2018-02617

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Tailoring and Characterisation of Bioelectronic Interfaces

Markov, A. (Corresponding author)FZJ*

2018
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich
ISBN: 978-3-95806-298-6

Please use a persistent id in citations: http://hdl.handle.net/2128/18469  urn:nbn:de:0001-2018050932

Abstract: An in-depth understanding of the interface between cells and implantable surfaces is one of the keys for coupling electrically excitable cells and bioelectronics devices. Recently, different approaches for the tailoring of surface properties to enhance the cell adhesion or create biocompatible surfaces have been introduced. These approaches aim for instance to control the cell growth or stimulate and record electrical signals emanating from the cell. Nevertheless, it still remains an open question how to create an ideal surface in a precisely controllable way for cells to couple mechanically or/and electronically to various materials or electronics. Here, we first present a novel in situ and extremely sensitive detection method for the analysis of the electronic properties of molecular layer during the molecular layer deposition using an inhouse engineered and automatized molecular layer deposition (MLD) setup that allows to perform all process steps including surface activation, deposition of different molecules from the gas phase, and the desorption of superfluous molecules, resulting in the formation of a molecular selfassembled monolayer (SAM) without braking the vacuum. The method not only allows monitoring and optimizing the deposition of organic layers but also demonstrates the high potential of organic SAMs for instance in form of organic high-k layers in electronic devices (e.g. 𝜀$_{SAM}$ ≃ 51 in case of APTES). Second, using this method, we modified the surface and surface properties of silicon oxide and polyimide by growing self-assembled monolayers comprising various compositions of two different molecules – APTES and GLYMO. The properties of the resulting mixed molecular monolayers (e.g. effective thickness, hydrophobicity, and surface potential) exhibit a perfect linear dependence on the composition of the molecular layer demonstrating that the surface properties can be tuned with these molecular layers. Third, coating the mixed molecular layers with poly(L-lysine) (PLL) shows that the density of polymer which is commonly used as buffer layer for cell adhesion and growth, can be controlled by the composition of the organic layer as well. This indicates that the method might be an ideal way to optimize inorganic surfaces for bioelectronics applications. Finally, we used the mixed molecular self-assembled monolayers to control the growth of neuronal cells and enhance the cell-chip communication. We demonstrate a strongly improved cell coupling and obtained high signals (up to 10 mV) for the action potential of HL-1 cells on multi electrode structures (MEA) covered with the mixed molecular layers. Additionally to this promising results in biocompatibility, the SAM covered MEAs could be reused for further cells experiments which would lead to increased productivity and reduced costs of the cell experiments. In conclusion the novel MLD technology with in situ deposition control seems to be a very powerful tool and might pave the way to improved or even novel bioelectronics applications ranging from bio- and molecular sensors to bioelectronics platforms that allows electronic interfaces with biological objects.

Note: Universität Köln, Diss., 2018

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Contributing Institute(s):

1. Bioelektronik (ICS-8)

Research Program(s):

1. 899 - ohne Topic (POF3-899) (POF3-899)

Appears in the scientific report 2018

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